Richard Denison, Ph.D., is a Lead Senior Scientist.
In contrast to the Environmental Protection Agency’s (EPA) asserted clean bill of health for Pigment Violet 29 (PV29) in its draft risk evaluation, authorities under the European Union’s REACH program have formally declared the chemical to be a suspected persistent, bioaccumulative and toxic (PBT) substance and a suspected very persistent and very bioaccumulative (vPvB) substance. Either designation, if confirmed, would classify PV29 as a substance of very high concern (SVHC) under the EU’s REACH Regulation.
In EDF’s earlier comments on EPA’s draft risk evaluation, we noted that PV29 had been proposed to be so listed under REACH and to undergo a full substance evaluation in 2021. Since we filed those comments, the European Chemicals Agency (ECHA) has published an update to its Community Rolling Action Plan (CoRAP) that now formally designates PV29 as a “suspected PBT/vPvB” that will be subject to a full substance evaluation. The listing is accompanied by a “justification document” for PV29’s designation.
The justification document, prepared by the Belgian Competent Authority (BE CA) under REACH and endorsed by REACH authorities, echoes many of the concerns about PV29 and EPA’s draft risk evaluation that EDF had raised in our earlier comments.
BE CA notes that “the registrants [of the chemical under REACH] state in their dossier that the substance[] [is] neither soluble in water nor soluble in organic solvents, therefore a very low bioavailability is expected.” But with respect to water solubility, BE CA goes on to state that it considers “the reliability of the water solubility and partition coefficient data for [PV29] as questionable” due to the divergence of values derived from both direct measurements and estimations using predictive models.
Water solubility: The Belgian authority specifically questions the registrants’ reliance on the single water solubility value of 0.01 milligrams per liter – the very same value EPA relies on extensively in its draft risk evaluation to dismiss a host of potential concerns. (We again note with particular concern the registrants’ selective deletion of much higher water solubility values for PV29 from two study summaries in its dossier – deletions that EDF discovered and documented in a recent blog post.)
BE CA concludes: “Because the estimated values substantially diverge from the value given in the registration dossier and because water solubility is a crucial element, it seems appropriate not to use the value presented by [the registrants] as an argument to deny the B-[bioaccumulation] concern.”
Bioaccumulation potential: Regarding solubility in organic solvents (an indirect measure of fat solubility and hence bioaccumulation potential), BE CA raises similar concerns about the lack of measured data and the variability of model estimates and concludes that “a reliable conclusion on the bioavailability of this substance is not possible based on the currently available data.”
BE CA flags as a concern the lack of experimental data on bioaccumulation in aquatic or terrestrial organisms. It also points to other data that suggests potential for bioaccumulation in air-breathing terrestrial organisms, including mammals.
Persistence: Regarding persistence, BE CA states: “Screening information does not indicate (bio)degradation. In view of the structure of the substance[], it is reasonable to expect that the P and the vP criterion are met for [this] substance[] and [structure-activity relationship] estimations support this concern.” The Belgian authority also notes that the registrants’ assessment “does not consider the possibility that in field conditions (slow) degradation of the parent compounds takes place.”
Toxicity: BE CA then notes the dearth of ecotoxicity data for PV29 other than for acute aquatic toxicity. Pointing to the substance’s “wide dispersive use, high tonnage and the environmental exposure,” BE CA concludes that a “potential risk [to] the environment cannot be excluded.”
Data gaps: Finally, BE CA identifies numerous additional needed data on toxicity, fate and behavior, and physical-chemical properties, consistent with our flagging of major data gaps that have not been acknowledged or addressed by EPA.
In finalizing its risk evaluation, EPA needs to take seriously and forthrightly address the data gaps, uncertainty and potential risks of PV29 including those flagged by EU authorities, rather than continue to rely on poor analysis and wholly insufficient information to support its questionable assertion that the substance does not present any unreasonable risks.